This application relates to a heat exchanger having a unique arrangement of its flow passages.
Heat exchangers are utilized in any number of applications and serve to cool one fluid typically by exchanging heat with a secondary fluid. Historically, heat exchangers have been formed of flow channels which have a relatively constant cross-section, and which also provide a relatively constant flow area per unit of total area.
One application for a heat exchanger is in a gas turbine engine. In gas turbine engines, a fan delivers air into a compressor and into a bypass duct as propulsion air. The air from the compressor is compressed and delivered into a combustor where it is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors, driving them to rotate.
The turbine section becomes quite hot and, thus, it is known to provide cooling air to the turbine section.
With recent advances in gas turbine engines, the turbine is exposed to hotter temperatures. Further, the turbine is exposed to higher pressures than in the past.
Thus, the cooling air being supplied to the turbine must also have a corresponding increase in pressure. However, when a higher pressure air is tapped from the compressor, the temperature also increases.
Thus, the cooling air must be cooled in a heat exchanger before being delivered to the turbine section. Known heat exchangers face challenges in providing adequate cooling.